By arachnoid cyst, physicians mean a collection of cerebrospinal fluid surrounded by the arachnoid (spider web-like meninges). The human brain has three layers of meninges, the middle layer of which consists of thin and white collagen fibers.
What is an arachnoid cyst?
The term arachnoid cyst refers to a cavity in the spinal meninges (arachnoid) that is filled with cerebrospinal fluid (CSF). This cerebrospinal fluid-filled factitious protrusion of the meninges may be congenital or result from external exposure to injury, surgery, or disease. They usually go undetected, but can also increase in size and cause discomfort. Cysts are differentiated between intracranial and spinal meningeal. Accordingly, an intracranial arachnoid cyst is located within the skull or inside the skull. Spinal meningeal arachnoid cysts are located within the spine (intraspinal) but outside the spinal cord (extramedullary). They contain cerebrospinal fluid (CSF).
Causes
Arachnoid cysts are commonly found as congenital malformations in the arachnoid (spider web-like meninges) that develop in the third trimester during early infant development. Reasons for cyst formation may include medications, drugs, or effects of radiation exposure. Arachnoid cysts are also associated with the consequences of meningitis. Due to malformations, a bubble-like structure develops in the middle meninges where cerebrospinal fluid (brain water) collects. As the water increases, an arachnoid cyst develops and is found either spinal or intracranial. Arachnoid cysts often show near the Sylvian fissure. Other causes include inflammation of the brain (meningitis) and spinal cord nerve cell fibers, circulation problems between the right and left hemispheres (corpus callosum), or inherited autosomal dominant connective tissue disease (Marfan syndrome).
Symptoms, complaints, and signs
Symptoms due to arachnoid cysts usually rarely appear. However, a large number of cysts tend to be discovered incidentally as a result of an MRI or CT scan. Once an arachnoid cyst increases in size, displacing surrounding tissue and organs, symptoms are indicated. Depending on the localization, it manifests itself in a very differentiated symptomatology. Cystic enlargements can occur at different locations intracranially (within the skull), most frequently in the area of the temporal brain. Sometimes they also occur in the area of the sellar region behind the cerebellum. Intracranial arachnoid cysts can sometimes cause symptoms such as headache, increased intracranial pressure with nausea and vomiting. They can also trigger increased fatigue, epileptic seizures, visual disturbances, speech disorders or symptoms of developmental delay as well as hormonal disturbances in the form of premature pubertal development. Sometimes patients also stand out due to personality changes. Spinal arachnoid cysts can negatively affect the spinal cord and the circulation of cerebrospinal fluid by exerting permanent pressure on the nerve roots. Depending on the location, pressure on the spinal cord or nerve roots causes radiating pain to extremities such as arms and legs, gait instability, sensory disturbances. Paralysis symptoms or even disturbances in bladder and bowel function. Sometimes external injuries are also decisive for the development of a cyst. In particular, minor injuries can lead to hemorrhage. However, often no symptoms are found, so that the arachnoid cyst is discovered rather by chance.
Diagnosis and course
Two important methods are used when an arachnoid cyst is suspected. Because of the precise soft tissue imaging, magnetic resonance imaging is often recommended. This procedure uses magnetic field technology to create a three-dimensional model of the vessels that specifically detects dilations in the brain or spinal cord. This reveals the cyst as a fluid-filled space. In rare cases, the condition between the cyst and the outer cerebrospinal fluid spaces is also examined by contrast medium enrichment of the cerebrospinal fluid. The contents of the cyst are imaged on MRI with the same intensity as those of the cerebrospinal fluid (CSF), and the contrast agent clearly reveals the cyst wall.Adjacent tissue structures are included to differentiate the diagnosis. As an alternative procedure, ultrasound examination is the focus of attention, especially for infants and children. The reflective sound waves produce images of structures within the body. Diagnostic sonography of arachnoid cysts takes only a few minutes. Once the presence of cysts is diagnosed, the physician will take further steps. There will be a subsequent neurological examination to check the functions of the brain and spinal cord to rule out any possible impairments that may still be unnoticed. This is followed by checks on the patient’s reflexes, sensitivity and motor functions. A blood sample with determination of inflammatory parameters also provides evidence of an arachnoid cyst.
Complications
In most cases, arachnoid cyst symptoms and discomfort occur only when the cyst grows. For this reason, only a delayed or incidental diagnosis is usually possible. In most cases, the enlargement of the cyst causes severe headaches due to the increased intracranial pressure. Likewise, patients suffer from vomiting and nausea and are extremely limited in their daily life. The severe headaches can lead to concentration disorders or sleep disturbances. Epileptic seizures also occur, which are associated with fatigue. As a rule, it is not possible to compensate for this fatigue with sleep. Visual disturbances may also occur suddenly. In children, developmental and intelligence disorders occur due to the arachnoid cyst. In some cases, a patient’s personality or basic attitude may also change significantly, which can have a negative effect on social contacts. Furthermore, paralysis occurs in various parts of the body. These can lead to restricted movement or gait disturbances. Often, patients also suffer from word-finding and speech disorders. The complications may persist even after the cyst is removed if it is done late. Consequential damage can be avoided if the cyst is removed early.
When should you see a doctor?
An arachnoid cyst does not necessarily need to be treated. However, if symptoms occur, a doctor must diagnose the cyst and remove it if necessary. Typical symptoms such as headache, impaired vision and speech, nausea and vomiting, fatigue, and epileptic seizures indicate a serious cause. While it is rarely an arachnoid cyst, there is almost always a condition that needs to be evaluated and treated by a physician. It is therefore advisable to see a doctor with unusual symptoms that persist for more than a few days. A diagnosed arachnoid cyst should be observed. If hormonal disturbances, symptoms of a developmental disorder or above-mentioned complaints suddenly appear, the cyst may have enlarged. At the latest, surgical removal of the growth should be performed. Other warning signs that require immediate medical clarification are sensory disturbances, paralysis and unsteadiness in gait. The same applies to sudden pain in the limbs and disturbances in bladder and bowel function. If these complaints occur, the following applies: off to the family doctor or neurologist and have the cause determined.
Treatment and therapy
Treatment and therapy first require a causal clarification. For this purpose, it is necessary to carefully examine the patient’s current general condition and the risk factors for the appropriate therapy. Arachnoid cysts should be treated surgically only if symptoms occur. Cysts discovered by chance require regular control examinations by means of imaging techniques. However, as soon as the cyst causes displacement that impairs blood circulation or even cerebrospinal fluid circulation, surgical treatment is necessary. Various procedures are available for this purpose. Endoscopic cyst fenestration is a minimally invasive and at the same time gentle method. The cyst wall is opened endoscopically to create a wide connection (marsupialization) to the natural cerebrospinal fluid spaces of the brain base (cisterns) or to the cerebral ventricles (cysto-ventriculo-stomy). To create. If there is a dermal cyst wall, the microsurgical surgical technique becomes necessary. In rare cases, creation of a cystoperitoneal shunt is performed.This is a catheter that is inserted into the cyst. This directs the fluid by means of a pressure valve under the skin to the abdominal cavity, where the draining cerebrospinal fluid is absorbed. This method achieves tremendous relief of cerebrospinal fluid outflow obstruction.
Outlook and prognosis
The prognosis of an arachnoid cyst is generally considered good. In the majority of cases, the cyst is removed immediately after diagnosis without further adverse effects, and the patient can be discharged as cured. The procedure is mostly uncomplicated and requires little effort. The subsequent wound healing takes several weeks. After that, the affected person is free of symptoms. This prospect of healing depends on the location of the cyst, the size of the cyst and the patient’s state of health. The older the affected person is and the more previous diseases are present, the less favorable is the healing process. Nevertheless, in normal cases, the arachnoid cyst is also completely removed permanently. If the cyst is located in an area that is difficult to access, the likelihood of a good prognosis decreases. Removal can be associated with serious complications and lead to lifelong impairments. The chance of recovery is also reduced if the arachnoid cyst has already caused functional disturbances in the body. These often cannot be corrected after removal. Without treatment, there is a risk of further growth of the cyst. This increases the risk of physical disorders and irreparable damage. In severe cases, the patient is at risk of life-threatening conditions.
Prevention
Congenital arachnoid cysts cannot be avoided by prevention. However, if their existence is known, regular monitoring by CT or MRI should be performed. Arachnoid cysts due to existing diseases, such as hypertension in diabetes mellitus, can be limited by primary treatment of the underlying disease. This includes a conscious change in lifestyle or, in the case of pronounced hypertension, the use of drug therapy. With timely diagnosis and subsequent surgery, the quality of life of those affected can be enormously improved.
Aftercare
Arachnoid cysts are harmless in most cases and accordingly do not require intensive treatment or follow-up care. If the cysts have already been diagnosed, follow-up by a neurologist should be performed once or twice a year. If symptoms occur, surgery in a specialized clinic may be necessary. After this procedure, follow-up is limited to examining the brain by ultrasound and monitoring medication. In addition, it must be ensured that the removal of the cysts has not led to neurological symptoms. The patient should initially take it easy and watch for any unusual symptoms. Follow-up care also includes keeping a diary of complaints. This can be used to track whether cysts have formed again months or years later. If this is not the case, follow-up can be discontinued. In case of recurrence, therapy can be resumed if the new cysts cause health problems. Normally, however, arachnoid cysts are uncomplicated and require only irregular follow-up. Patients should contact their physician if they experience any discomfort after removal of a cyst or if any side effects or drug interactions occur during drug treatment.
Here’s what you can do yourself
Before an arachnoid cyst can be treated, a comprehensive evaluation must be performed by a physician. Among other things, the actual therapy can be supported by strict personal hygiene and adherence to the doctor’s instructions. Since the cysts can occur in several regions of the body, the patient should check the armpits, the back, the intimate area and other areas of the body that are difficult to see daily for conspicuous skin changes. Usually, an arachnoid cyst occurs in the area of the brain, but in conjunction with other diseases, serious skin conditions can develop that affect the entire body. For this reason, a careful examination must be performed by a specialist in neurology. People who have meningitis should inform the doctor about it.Further measures depend on the type and extent of the cyst. Small cysts can be surgically removed and usually promise a positive prognosis. Larger cysts, on the other hand, can cause neurological disorders that must be treated separately. The patient should consult a physiotherapist at an early stage and take preventive measures. Therapeutic counseling significantly reduces the risk of concomitant mental symptoms.
